Involvement of Cot activity in the proliferation of ALCL lymphoma cells

Highlights: → We show here that ALCL lymphoma cell lines present high levels of Cot (MAP3K8). → We show that Cot mediates the constitutive Erk1/2 activation in SUDHL-1 cells. → Inhibition of Cot activity reduces the number of cell divisions in SUDHL-1 cells. → Cot controls the activation state of p70 S6K and JunB expression in SUDHL-1 cells. -- Abstract: Anaplastic large-cell lymphoma (ALCL) cells overexpress CD30 on their cell surface, show increased levels of activated Erk1/2 and of JunB; participating JunB in the proliferative capacity of these lymphomas. Here, we show that ALCL lymphoma cells also present high expression levels of the proto-oncogenic Cot (MAP3K8). Using pharmacological drugs as well as the RNA interference technique we show that Cot protein is responsible for the constitutive Erk1/2 activation in the ALCL lymphoma cells, SUDHL-1. Besides, inhibition of Cot activity reduces the number of cell divisions which is achieved, at least in part, by the control that Cot exercises on the activation state of p70 S6K and on the expression levels of JunB. Since Cot represents an alternative mode, independently of RAF, to activate Erk1/2, all these data strongly suggest that molecular targeting of Cot may be a potential new specific strategy for ALCL lymphomas therapy, without the fully disturbance of the Erk1/2 function.